Removed deprecated MT memory controller [ci patch inc]

[HyperWinX]

Removed deprecated memory controller based on mutexes, removed all tests that use it.

[mentatbot]

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[mentatbot]

I've reviewed the changes in this PR. This is a clean removal of the deprecated MT memory controller:

• Removed MemoryControllerMT.hpp file completely
• Updated CPU constructor to unconditionally use the ST memory controller
• Removed the class forward declaration in CPU.hpp
• Removed all associated test fixtures and test files

This is a good cleanup that simplifies the codebase by removing deprecated code. I'll wait for CI to complete to ensure everything works as expected.